Radiation Therapy | Combined with Surgery and Chemotherapy

Radiation Therapy is also used as an adjuvant therapy: 
RT is often used in combination with surgery and/or chemotherapy.

a. When combined with surgery:
RT may be given prior to (preoperative), following (postoperative) or during (intraoperative) surgery.

• Preoperative RT was commonly used earlier, but is used lesser now. For example large, borderline resectable tumors, rectal cancer and soft tissue sarcomas

• Postoperative RT is used in many tumors  including tumors of the central nervous system,head and neck, breast,lung, genitourinary, and gastrointestinal tract.RT is given when there are close margins of tumor, residual disease, and lymph node involvement.Disadvantages of postoperative RT are that it may cause delay in therapy until wound healing is complete and reduced blood supply of tissues following surgery.

• Intraoperative RT includes  delivery of a single, large fraction or RT during surgery.This is done with either a treatment machine in the operation theater or by transporting the patient to the RT department during surgery itself.An important benefit of this type of therapy is that normal tissues  can be placed out of the treatment field.For example, small bowel can be conveniently placed outside the RT field.A disadvantage is of this treatment is that only one large dose is given and the benefits of RT given in fractions are not achieved.Although, this treatment has shown remarkable results in retroperitoneal soft tissue sarcoma. Brachytherapy can also be used at the time of surgery. But again, the time for wound healing has to given before other treatments begin.



Radiotherapy with Surgery(intraoperative)
image courtesy-www.radical.com

b. When combined with chemotherapy:

• Chemotherapy may be given before RT (neoadjuvant therapy), during (concomitant therapy) or following RT (maintenance).
• Chemo-radiotherapy has shown to eradicate micrometastasis and improve local control.
• Neoadjuvant chemotherapy has been used in early stage non–Hodgkin’s lymphoma and small cell lung cancer.
• A potential advantage is that the bulky tumor sites can be reduced thus allowing smaller treatment volumes. However, lot of researches suggests that concomitant chemo-radiotherapy is preferable overall.
• For example, this is used in locally advanced cancer of the lung, head and neck,esophagus,bladder, and cervix.

Combination of the two result in various interactions like:

• after radiation, when chemotherapy is given,there is decreased tumor cell repopulation.
• after using both, there is shrinkage of tumor and increased drug delivery to the tumor.
• there is early eradication of tumor cells, hence reducing the chances of the tumor cells becoming resistant to drugs and radiation.
• even if the tumor cells are resistant to one type of therapy, they will be eradicated by the other.
• if the radiation damage is sub-lethal, then chemotherapy prevents the cells from undergoing any sort of repair or recovery.

All three modalities are combined in cases like locally advanced breast cancer, where neoadjuvant chemotherapy is given, followed by surgery and then postoperative RT is given.

Also read 

12 causes of cancer.

What is Radiation oncology?

What are the side-effects of Radiation therapy?

What is Brachytherapy?

Brachytherapy step-wise procedure 

Brachytherapy for prostate cancer.